1. Field of the Invention
The present invention relates to a film pack holder and more particularly to a film pack holder in which a film pack, wherein a plurality of sheet film units are piled and housed, is set.
2. Description of the Related Art
There is a film pack holder which is disclosed in a Japanese Patent Application Laid-open No. 5-341381. The film pack holder is set in an exposure frame of a large-format camera after the lid of the film pack holder is opened and a film pack is set in a slide frame within a main body of a holder. At the time of photographing, a slide of the film pack is pulled out, and the first sheet film unit is exposed via an exposure opening of the lid.
A display mechanism is provided in the film pack holder so as to display a mark indicating that a preparation for photographing is completed. The display mechanism has a nail which is engaged with the slide of the film pack 1. The nail is moved in connection with the opening and closing of the slide, so that the mark can be displayed.
Furthermore, a pair of nails are provided at the main body of the holder and the lid in order to lock the main body of the holder and the lid when the lid is closed. The pair of nails provided at the lid is formed at both ends of the plate-shaped nail main body, which is arranged at the lid in such a manner to move back and forth freely. The nail main body is moved by the pressure from the knob, which is provided at the center against the force of the torsion coil spring in a direction in that the lock is released.
However, there is a problem when a hand touches the nail portion in the display mechanism and moves the nail portion carelessly. When the film pack is set after the hand touches the nail portion, the mark indicating the completion of the photographing preparation is displayed even if the preparation has not been completed yet. As a result, the photographer starts the photographing by mistake.
Furthermore, the film pack holder is unstable because the nail main body is supported by only one torsion coil spring. Therefore, when the knob is pressed, the nail main body shakes with the attachment portion of the torsion coil spring being a center. So, there is a problem in that the nail main body does not move back and forth smoothly and the lock cannot be released.